It is conventional to incorporate finely powdered grains or matting agents into the protective layer of a photographic element to increase the surface roughness so as to reduce self-adhering of the material, to reduce sticking of the material to manufacturing and processing devices, to improve the antistatic properties of the material, and to improve the vacuum adhesiveness of the material in contact exposure to prevent Newton's rings. The matting agents are commonly very small particles of organic or inorganic materials, such as silicon dioxide, magnesium oxide, titanium dioxide, calcium carbonate, poly(methyl methacrylate), poly(vinyltoluene), poly(methyl methacrylate-co-methacrylic acid), and so on.
This "matting" of the surface layer suffers, however, from various disadvantages. For example, it reduces the transparency of the photographic elements after processing and increases the graininess of the picture. This limits the amount and size of matte which can be incorporated into the protective overcoat. Many attempts therefore have been made to find processing removable polymer particles (soluble matte) which can be removed from the surface during processing, for example, in high pH processing solutions. The high concentration of processing removable matte is needed especially when the photographic elements are used at relatively high levels of moisture and at relatively elevated temperature of from 30.degree. to 40.degree. C. It is also needed to prevent adverse photographic effects, such as desensitization or hypersensitization, when the materials are rolled up.
However, the use of a high level of processing removable matte does not prevent photographic elements from ferrotyping or blocking after processing. This has become important in recent years as more and more processed photographic elements are stored or housed in cartridges with which they come into direct contact. Moreover, the use in the protective overcoat of a higher level of processing removable polymer mattes which contain carboxylic acid groups tends to cause self damage of the photographic elements by scratching or abrading the surface on the opposite side, and to cause damage to manufacturing and finishing apparatus. Therefore, it is desirable to use a minimum amount of processing removable matte in the protective layers of photographic elements even for ferrotyping protection in the raw (unprocessed) state.
The present invention provides a photographic element with good ferrotyping performance both before and after processing, thus allowing the element to be used under harsh application conditions with superior performance, and in particular after processing with favorable handling and storage.